My first suggestion: look further into the future.
In the case of the co-founder, if he/she will play an important role taking the product to market, wooing investors, keeping the team motivated, through the life of the company, that's a co-founder. If this is an important person in product development but isn't a foundational member of the company then it's a key early employee. You can call that person whatever you want but it'll make a difference in equity awards.
In the case of the the other employees, don't just look at key employees over the next 6-12 months, imagine success over the next 2-3 years. Let's say you'll be at 40 employees in 3 years; create a plan that awards your dev staff, sales staff, managers, etc. Have this approved by the board. This might change but I often see companies getting squeezed in equity awards because there wasn't proper planning and early awards were too large.
Consider your dilution through the funding rounds. You need to determine your stance on ownership. What's your tolerance for dilution.
Here are some resources for you:
A startup equity calculator that will provide some good questions to ask yourself: http://foundrs.com/
Spreadsheet for calculating founder split (link at bottom of this) http://al.bsharah.com/co-founders-its-time-to-split-that-equity/
Dilution tool that may help you look to the future cap structure: https://smartasset.com/infographic/startup
I've seen a number of startups in your situation and it wouldn't be far off to have an employee pool of 15%, two co-founders at 10% each, and you at 65%. Yours will of course vary from this but just to get you in the wheelhouse. Of course, all should follow a vesting schedule, typically 4 yrs, 1 yr cliff, limited exercise period upon departure from company.